Problem: When Sending Emails a Single Wrong Address Stops Further Processing

Problem

When sending an Email to multiple (internal) recipients (mixed existing and non-existing users) by using the "To:, CC: oder BCC: fields sending of the email fails if just one recipient email address does not exist.

Solution

Step 1

Edit /etc/postfix/main.cf.local and add the following line:

local_recipient_maps =

Step 2

Restart Postfix

systemctl restart postfix

Note: By disabling this check Postfix will accept ALL email for local delivery and reply with bounce emails if a user does not exist. This might not be desireable as it will accept all sort of spam, junk and unsolicited messages,

Root Cause

Postfix by default checks if local addresses exist in the user database. If they do not exist, Postfix refuses to accept the email. The above setting skips this check in the first steps and accepts all emails. For non existing users Postfix will then send a bounce message later to inform the sender about the non existing user.

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